Although all patients will receive anticoagulant treatment immediately after the diagnosis is established, morbidity and mortality are still disturbingly high when circulatory and/or respiratory symptoms accompany PE, or when hemodynamically stable PE patients have echocardiographic signs of acute right ventricle overload. There are no generally accepted guidelines for additional treatment options in these patients with moderate-to-severe PE. Thrombolytic therapy is recommended by many when hemodynamic symptoms are severe, but its effectiveness has never been proven in a controlled trial. In patients with moderate-to-large PE associated with echocardiographic signs of right ventricle overload, but who are still circulatory stable, mortality is increased, but thrombolytic therapy appears not to be beneficial.